737-700 Check MCP ALT

[Guest mrants]

Anyone know what this means?(Check MCP ALT).It appears on the FMC screen, usually during descent.Can someone please give me an example as to why I would get this message?Thanks.Tony.

[Manny 1,293]

Just prior to TOD (Top of descent), the MCP altitude should be set to your minimin altitide like 200 or something.Otherwise the autopilot will not desend below what you have set in the MCP.so before reaching TOD if you don't lower your MCP altitude. It will not descend.I think.Manny

[Guest mrants]

Thanks for replying Manny.However I have the autopilot altitude set to 3000 feet before TD, and the aircraft begins descending ok.I only get the message (Check MCP ALT) during descent.Tony.